Blast furnace hearth and bosh



sept- 1935' G. M. HARRIS 2,052,928

BLAST FURNACE HEARTH AND BOSI-i Filed Dec. 20, 1955 3 Sheets-Sheet 1'INVENTOR.

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ATTORNEYS p 1935- G. M. HARRIS I 2,052,928

BLAST FURNACE HEARTH AND BOSH F 'iled Dec. 20, 1935 5 Sheets-Sheet 2INVENT OR.

ATTORNEYfi v Sept. 1, 1936.

G. M. HARRIS s Sheets-Sheet 3 Filed Dec. 20, 1935 INVENTOR.GPIRNErrMfiR/P/a ATTORNEY5 Patented Sept. 1, 1936.

UNHTED STATES PATENT OFFICE Garnett M. Harris, Birmingham, Ala.Application December 20, 1935, Serial No. 55,480

' 15 Claims.

This invention relates in general to blast furnaces of the characterused for the smelting of ores such-as iron ore and the like and moreparticularly to those parts of the furnace known as the crucible and thebosh.

The conventional blast furnaces of the modern type in general use forsmelting iron ore usually comprise .a refractory lined structureapproximately ninety feet in height and about twentyfive feet Outsidediameter. Such furnaces usually comprise elements corresponding tohollow cylinders and hollow truncated cones superposed on each other.The bottommost section of the furnace is usually referred to either asthe hearth or the crucible and in common practice it is usually abouteighteen feet in diameter and about twelve feet high. Liquid iron andslag collect in this crucible portion and are withdrawn at regularintervals through the iron and cinder notches located near the bottomand top of the crucible.

Above the crucible portion, there is usually-aw portion corresponding toa hollow truncated cone whose walls diverge upwardly, known as the bosh.Above the bosh, there is a long section known as the stack, resembling ahollow truncated cone whose walls converge upwardly. At the top of thestack, suitable charging bells and platforms are ordinarily provided.

The stack of the furnace is usually insulated with a layer of firebrickapproximately four feet thick, while the bosh and crucible portions areconsiderably thinner. However, they customarily have refractory liningswhich are water cooled by incorporating in the structure hollow copperblocks through which .water is continuously circulated.

Near the top of the crucible or hearth, there is a circumferentialseries of tuyres through which air is forced under pressure from anannular pipe surrounding the furnace, commonly known as a bustle-pipe.The several .tuyeres are suitably connected with the bustle-pipe and theconnections are customarily so arranged that as 45 the tuyeres burn outthey can be readilywithdrawn and new ones inserted.

In all iron blast furnaces or other ore smelting furnaces of which Ihave knowledge, the air blast is directed inwardly from the exterior. ofthe fur- 50 nace toward the central portion thereof.

My invention contemplates a radical departure from the design andarrangement of blast furnaces now in general use in that instead'ofdischarging the blast air only from the outer por- 55 tion of thefurnace inward, I provide means whereby a separate series of tuyeres areoperative to discharge blasts of air from the central zone of thefurnace outwardly. This is considered to be highly desirable in order tocause the blast to penetrate practically the entire cross sectional areaof the crucible. This will result in a more 5 even burning of the cokecharged to the furnace and a more even or gentle settlement of the stockand a better distribution of the gases as they rise through the stack ofthe furnace above the tuyere level. And the whole operation of the 10furnace would be improved and its efiiciency considerably increased.

In the old furnaces of the prior art hereinabove briefly described, theair blast performs three major functions, one, preheating the ore, cokel5 and limestone, deoxidizing the metallic oxides of the'ore andconverting the resulting iron and slag to a molten state. The rawcharging materials, such as iron ore, coke and flux such as limestone,are charged into the top of the furnace and descend countercurrent tothe great volumes of carbon monoxide and nitrogen generated near thelower part of the furnace.

As the charging materials descend countercurrent to the rising reducinggases, the more 25 easily reduced high oxides come in contact with thegas of the lowest reducing power, and the gas richest in carbon monoxidereacts with the ore in the final stages of reduction at the lower levelsof the furnace. This well known phe- 30 nomena results in an excellentutilization of the reduciiig power of the gases. and is in a measurelargelyresponsible for the almost universal utilization of theconventional type of iron smelting blast furnace above briefly referredto. 35

It is fairly well recognized that the seat of life of a blast furnace isin the neighborhood of the combustion zones in front of the tuyeresbecause the heat as well as the reducing gases for carrying on theprocess are generated in this part 4 of the furnace. But, in the typesof furnaces heretofore generally used, there is an inactive zone, bywhich I mean, there is a zone wherein. combustion is not taking placethroughout the entire cross sectional area of the furnace at the tuyerezone. Studies and investigations establish the fact that combustionzones are about the same area for a small furnace as for a largeone.Thus, in conventional furnaces, there is an inactive zone at the tuyerelevel of the furnace. With a furnace having a crucible diameter oftwenty-five feet, this inactive area represents a large fraction of thetotal area. But, in spite of this crucible condition in this artcrucible areas have been increased until the furnace of the type usedten years ago, which would produce about six hundred tons of iron perday, now produces about one thousand tons per day. Such large furnaceshave operated smoothly and efliciently.

But, the gain in the furnace production has not been in proportion tothe increase in crucible area and there has been little or no realimprovement in the efllciency of the furnace as measured by fuelconsumption.

In the furnace embodying my invention, the crucible is materiallyincreased in diameter. But, its area may be decreased or increasedbecause I so arrange the structure of the furnace that an annularcrucible is provided and. I arrange the tuyeres in such a way that oneseries of tuyeres directs the air blast inwardly and another set'oftuyeres directs the blast outwardly and I arrange the tuyeres in thedifferent sets or series in a staggered relationship so that the 'zoneof influence of the blast from the tuyeres is felt virtually throughoutthe entire sectional area of the hearth or crucible. This comprises ablast furnace structure having an annular crucible and an annularbosh-and with provision for a tuyere room in the center of the furnacewhere workmen can enter for the purpose of changing tuyeres or observingthe action of the furnace through suitable peep-holes in the tuyeres.The top of this tuyere room, to withstand the heat, is provided with awater cooled dome and the innerbosh wall is water cooled. And fresh airis supplied to the tuyere room, so as to maintain theatmosphere in suchcondition that the workmen can perform their necessary duties in thislocation, which it will be remembered is surrounded by molten iron, ironore, flux and other stock materials in the annular bosh of the furnace.

A furnace embodying the above described and other features of myinvention is illustrated in the accompanying drawings, in which- Fig. 1is a vertical longitudinal section through the improved furnace, thestack portion having been foreshortened, however, to enable showing ofthe bosh and crucible portions on a legible scale; Fig. 2 is a crosssection of the crucible and bosh portions of the furnace, at a scalemuch greater than that of Fig. 1; Fig. 3 is a horizontal section takenthrough the furnace at the tuyere level. v

With reference to the detailed features of the structure illustrated,lll represents a suitable foundation portion which supports theconcentric annular outer and inner wall portions l I and I2,respectively, of the crucible portion of the furnace. Above thecrucible, there are outer and inner annular bosh walls I3 and t4, theouter bosh wall diverging upwardly and outwardly and the inner bosh wallconverging inwardly and upwardly. Above the bosh wall, the furnace issubstantially of conventional construction and includes the usual stackwall 16 and the usual outer shell l'l. At the stock line, I provide aconventional form of stock line armor I81. And

blast air delivered to the outer circumferential series of tuyeres 2|.These tuyeres are of conventional type and are positioned in a.conventional manner in water cooled tuyere coolers, indicated at 2|. Allof the tuyeres of the seshown or described in detail.

outer walls II and I3 of the crucible and bosh, re-

ries indicated by the numerals 2| direct the blast inwardly into theannular hearth or crucible 22.

An inner series of tuyeres 23 are positioned in suitable tuyere coolers24 and they each direct an air blast into the crucible in a directionextending radially outward from the center of the furnace. The tuyeres23, as viewed in plan, are arranged in staggered relation to the tuyeres2| of the outer series. It is thus clear that in such an arrangement theblast coming from two di-.

rections will penetrate practically the entire cross section of thecrucible and the combined com-- bustion zones will practically coverthis area, hence all inactive spaces will be eliminated. This willresult in a more even burning of the coke, a more uniform settlement ofthe stock anda better distribution of the reducing gases as they arisethrough the stock above the tuyere level.

For supplying the blast air to the inner set of 20 tuyeres 23, I providea blast main 25 which communicates with a suitable supply of hot blastair. At its upper end, the pipe has a plurality of lateral brancheswhich communicate by means of fittings 26 with adjacent pairs of tuyeres2: as 2:

fully apparent from Figs. 2 and 3. This pipe enters through a tunnel 21formed in the foundation ill of the furnace, which tunnel also serves asmeans of access and egress for the workmen, who

must enter the central tuyere room 28. This 36 is lined on the interiorwith a hollow metal shell 34 conforming in shape to the dome. Thisjacket is supported by a metal lining indicated at 35. This lining is ofstepped formation and is provided with a plurality of inward extensions36 which are water cooled. These resemble the conventional forms ofinsert members, indicated at 31, which extend inwardly into the outerbosh wail l3, so as to prolong the life of the bosh wall.

A water supply pipe 38 enters through the tunnel 21 and extends upwardlythrough the shaft 23 and into the central tuyere room and connects in asuitable manner with the water jacketed shell 34 and with the inserts 36in any suitable manner by the use of any conventional form of pipefittings and connections which need not be r Fresh cooled air issupplied to the tuyere room 23 by pipe 39, so as to maintain livableworking conditions in this room, which must be occupied by blast furnaceattendants, in order to permit inspection of the tuyeres and the removaland re- 00 newal of the same when necessary. The furnace is providedwith the usual iro notch 40 through which the molten iron isperiodically withdrawn and also a typical form of cinder notch 4|,through which a slag is discharged each time the furnace is tapped.

The exterior of the furnace is formed with the usual mantle 42 which iscarried by pillars 43 spectively.

While I have described quite precisely the design and arrangement of thefurnace herein illustrated, it is to be understoodthat the drawings anddescription are to be interpreted in an illustrative rather than alimiting sense since various modifications may be made by those skilledin the art without departure from the invention as defined intheappended claims.

What I claim is:

l. A blast furnace for smelting ores comprising inner and outer wallsdefining an annular crucible, an annular bosh thereabove, a stack abovethe bosh and crucible, an outer series of tuyeres extending through theouter wall of said crucible and an inner series of tuyres extendingthrough the inner wall of said crucible.

2. A blast furnace for smelting ores comprising a pair of upright wallsdefining an annular crucible, a pair of bosh walls thereabove definingan annular bosh, a stack wall rising from the bosh wall, and respectivesets of tuyeres fordirecting air blasts into the annular crucible inrespectively inward and outward directions.

3. A blast furnace of the character described comprising a pair ofsubstantially concentric crucible walls defining an annular hearth, anupwardly and outwardly diverging bosh wall rising from the outer wall ofthe crucible and an inwardly and upwardly converging bosh wall risingfrom the inner wall of the crucible, an outer series of tuyeres fordirecting air blasts inwardly into the crucible, andan inner series oftuyeres for directing air blasts outwardly into the crucible.

4. A blast furnace of the character described comprising inner and outercrucible walls defining an annular hearth, an. outer annular bosh walldiverging outwardly and upwardly from the upper portion of the outercrucible wall, an inner annular bosh wall rising from the inner wall ofth crucible and having a dome-like roof defining a tuyere chamber, anouter set of tuyeres for directing an air blast inwardly into thecrucible, an inner set of tuyeres located in said tuyre chamber fordirecting air blasts outwardly into the crucible.

5. A blast furnace of the character described comprising inner and outercrucible walls defining an annular crucible, an outer annular bosh walldiverging outwardly andupwardly from the upper portion of the outercrucible wall, an inner annular bosh wall rising from the inner walls ofthe crucible and having a dome-like roof defining a tuyre chamber, anouter set of tuyres for directing an air blast inwardly into thecrucible, an inner set of tuyres located in the tuyere chamber fordirecting air blasts outwardly into the crucible, a foundation for thecrucible having a tunnel anda shaftway therein to permit the passage ofworkmen to and from the tuyre chamber. e

6. A blast furnace of the character described comprising inner and outercrucible walls definfor the crucible having a tunnel and a ehartwavtherein to permit the passage of workmen to and from the tuyere chamber.

7. A blast furnace of the character described comprising inner and outercrucible walls defining an annular hearth, an outer annular bosh walldiverging outwardly and upwardly from the upper portion of the outercrucible wall, an inner annular bosh wall rising from the inner wall ofthe crucible and having a dome-like roof defining a-tuyre chamber, anouter set of tuyres for directing an air blast inwardly into thecrucible, an inner set of tuyeres located in the tuyre chamber fordirecting air blasts outwardly into the crucible, a foundation for thecrucible having a tunnel and a shaftway therein to permit the passage ofworkmen to and from the tuyere chamber, and a water cooled lining forsaid shaftway.

8. A blast furnace of the character described comprising inner and outercrucible walls defining an annular hearth, an outer annular bosh walldiverging outwardly and upwardly from'the upper portion of the outercrucible wall, an inner annular bosh wall rising from the inner wall ofthe crucible and having a dome-like roof defining a tuyre chamber, anouter set of tuyeres for directing an air blast inwardly into thecrucible, an inner set of tuyres located in the tuyere chamber fordirecting air blasts outwardly into the crucible, a foundation for thecrucible having a tunnel and a shaftway therein to permit the passage ofworkmen to and from the tuyere chamber, and an air blast pipe extendingthrough said shaftway and having a plurality of branches communicatingwith the inner series of tuyeres.

9. A blast furnace of the character described comprising inner and outercrucible walls defining an annular hearth; an outer annular bosh walldiverging outwardly and upwardly from the upper portion of the outercrucible wall, an inner annular bosh wall rising from the inner wall ofthe crucible and having a dome-like roof defining a tuyre chamber, anouter set of tuyres for directing an air blast inwardly into thecrucible, an inner set of tuyeres located in the tuyre chamber fordirecting air blasts outwardly into the crucible, a foundation for thecrucible having atunnel and a shaftway therein to permit the passage ofworkmen to and from the tuyere chamher, and a pipe opening into saidtuyere room for supplying fresh air thereto.

10. A blast furnace of the character described comprising a foundationhaving inner and outer substantially concentric crucible walls definingan annular crucible, an outer bosh wall rising from the crucible wall,an inner upwardly and inwardly converging bosh wall rising from theinner crucible wall and having a dome-like roof defining a. tuyrechamber, a water cooled metallic lining for said chamber, an outer setof tuyres communicating with a bustle-pipe for supplying blast air tosaid outer series of tuyres, an inner series of tuyres located in saidtuyre chamber and an air blast pipe having a plurality of branches com-'municating with said inner set of tuyeres, a

tunnel below the crucible and a shaftway communicating with said tunneland said tuyere chamber so as to permit passage of workmen to and fromsaid chamber.

11. A blast furnace of the character described having inner and outerwall portions defining an annular crucible and an inner shaftway, innerand outer bosh walls rising respectively from the inner and outer wallportions, a stack supported by pillars carried by the foundation andrising above the outer bosh wall, an outer set of tuyeres for directingair blasts inwardly into the annular crucible. an inner set of tuyresfor directing air blasts outwardly into the annular crucible, a roofwhich with the inner bosh wall defines a tuyere chamber, a flooring forthe accommodation of workmen'in said chamber and an air blast supplypipe for the inner set of tuyres extending into said tuyere chamber.'

12. A blast furnace of the character described having inner and outerwall portions defining an annular crucible and an inner shaftway, innerand.outer bosh walls rising respectively from said inner and outer wallportions, a stack supported by pillars carried by the foundation andrising tending into said tuyere chamber, means for water cooling theroof of said tuyere chamber and means for discharging fresh air intosaid chamher so as to maintain a livable atmosphere therein.

13. A blast furnace for smelting ores comprising inner and outer wallportions defining an annular crucible and-an annular bosh, a stack 5above the bosh and inner and outer sets of tuyeres efiective todistribute air blasts over substantially the entire sectional area ofthe crucible.

14. A blast furnace for smelting ores comprising inner and outer wallportions defining an annular crucible and an annular bosh, a stackportion above the bosh. and vtuyeres eflective todistribute an air blastthroughout substantially the entire cross sectional area of said annularcru cible.

15. A blast furnace for smelting ores comprising inner and outer wallportions defining'an annular crucible,-an innerstructure which in con-Junction with theinner wall of the crucible de-.

fines an inner tuyere chamber, an outer annular 20 wall rising from theouter wall of the crucible, an inner set of tuyeres in said chambereffective to direct air blasts outwardly into the crucible and an outerset of tuyeres effective to direct air blasts inwardly into thecrucible. 25

GARNE'I'I M. HARRIS.

